This application claims the benefit of Korean Application No. 01-82249, filed Dec. 21, 2001, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an automatic document or paper feeder (referred to below as an automatic document feeder) applied to office machines such as a multifunction printer, a facsimile machine, a copier, etc., and more particularly, to a hinge apparatus to open and close an upper member such as the automatic document feeder used in the office machine, which can prevent the upper member from unexpectedly closing during the opening thereof.
2. Description of the Related Art
Generally, an office machine such as a facsimile machine, a multifunction printer and the like comprises a scanning apparatus to scan data recorded in a document, a facsimile apparatus to transmit the scanned data or receive data through a communication circuit, and a printing apparatus to print or output the scanned data, the data received through the communication circuit, or data inputted from a computer on a printing paper. Among these components, the scanning apparatus is an apparatus essential to transmit the data recorded in the document through the communication circuit or print them on the printing paper.
Referring to FIG. 1, there is illustrated a general scanning apparatus 1 which is used in an office machine such as a multifunction printer, a facsimile machine, and the like. The scanning apparatus 1 comprises an automatic document feeder 2 to automatically transport a document D into the inside thereof. The automatic document feeder 2 has a document-storing frame 5 to store the document D disposed at an upper part of the office machine and pick-up and transport rollers 6 and 6xe2x80x2 to pick up and transport the document D, a scanner 8 to read data from the document D transported through the automatic document feeder 2, a white roller 8xe2x80x2 to make the document D come into contact with the scanner 8, and a document-discharging part 9 to discharge the document D transported through the scanner 8 and the white roller 8xe2x80x2 to the outside of the document feeder 2.
As illustrated in FIG. 2, in the automatic document feeder 2, the components therein are generally disposed to be opened and closed by two hinge apparatuses 10 and 10xe2x80x2 mounted between a lower frame 3 of the automatic document feeder 2 and a main frame 4 of the main body of the office machine, so that attaching and detaching the document feeder 2 to and from the main body of the office machine or removing a jam generated therein during scanning of document can be easily carried out.
As illustrated in FIG. 3, FIG. 4 and FIG. 5, a conventional hinge apparatus 10 or 10xe2x80x2 comprises a fixing frame 16 having projected brackets 19 and 19xe2x80x2 secured with screws 20 and 20xe2x80x2 on fixing bosses 14 and 14xe2x80x2 formed at one side of a lower surface of the lower frame 3 of the automatic document feeder 2, a hinge body 26 inserted and settled in mounting grooves 41 and 41xe2x80x2 formed at the main frame 4 and having supporting guides 27 and 27xe2x80x2 projected upward from both sides of an upper part thereof, and a hinge shaft 11 having a fixing end 12 extended through a penetrated bore 18 of the fixing frame 16 and support holes 28 and 28xe2x80x2 in the supporting guides 27 and 27xe2x80x2 and then secured with an C-shaped ring 36 to rotatably support the fixing frame 16 and the hinge body 26 with respect to each other.
To prevent the automatic document feeder 2 from unexpectedly falling and closing by its own gravity when it is opened, the hinge apparatus 10 or 10xe2x80x2 is provided with a position-fixing member. The position-fixing member is composed of a position-fixing cam 17 integrally formed with the fixing frame 16 and having a penetrated bore 18 to receive the hinge shaft 11 and cam surfaces 21, 21xe2x80x2 and 22, a position-fixing plate 23 to maintain a position of the fixing frame 16 and guiding a movement thereof by engaging with the cam surfaces 21, 21xe2x80x2 and 22 of the position-fixing cam 17, and an elastic spring 25 to elastically press the position-fixing plate 23 against the position-fixing cam 17.
The cam surfaces 21, 21xe2x80x2 and 22 of the position-fixing cam 17 include first and second fixing cam surfaces 21 and 21xe2x80x2 formed as flat surfaces and a guide cam surface 22 formed as a curved surface. An upper surface of the position-fixing plate 23 is formed into a flat surface, so that it can be in face-to-face contact with the first and second fixing cam surfaces 21 and 21xe2x80x2 to restrain the movement of the fixing frame 16 when engaged therewith and in sliding contact with the guide cam surface 22 when engaged therewith.
Also, the position-fixing plate 23 and the elastic spring 25 are inserted and supported in a receiving opening 29 formed between the supporting guides 27 and 27xe2x80x2 of the hinge body 26, and the receiving opening 29 at a lower part thereof is stopped with a support cover 31 having a protrusion 32 to support the elastic spring 25. The support cover 31 is fixed to the hinge body 26 by screws 33 and 33xe2x80x2.
Operation of the hinge apparatus 10 and 10xe2x80x2 described above will now be explained.
As illustrated in FIG. 4, assuming that the lower frame 3 of the automatic document feeder 2 is closed against the main frame 4 of the main body, the position-fixing plate 23 is positioned in the position engaged with the first cam surface 21 of the position-fixing cam 17 by the elastic spring 25 to maintain the lower frame 3 in a closed position.
In this state, when one side end of the lower frame 3 is separated from the main frame 4 and raised by a user, for example, to remove a jammed document, the position-fixing cam 17 is rotated counterclockwise about the hinge shaft 11 supported in the support holes 28 and 28xe2x80x2 of the supporting guides 27 and 27xe2x80x2, and thereby the position-fixing plate 23 is separated from the first cam surface 21 of the position-fixing cam 17 and slid to come into contact with the curved guide cam surface 22.
When the lower frame 3 of the automatic document feeder 2 is further rotated and almost vertically positioned, the position-fixing plate 23 is engaged with the second fixing cam surface 21xe2x80x2. At this time, since the upper surface of the position-fixing plate 23 and the second fixing cam surface 21xe2x80x2 are elastically engaged with each other with the aid of the elastic spring 25 by a nip on the top of the position-fixing plate 23 having a certain length and width, the automatic document feeder 2 is prevented from freely falling and closing as long as there is no external force applied thereto. Thereafter, when an end of the fixing frame 16 is engaged with a corresponding side face of the hinge body 26, the lower frame 3 is not rotated any longer and the automatic document feeder 2 is maintained in an opened position.
Operation of closing the automatic document feeder 2 is carried out in the reverse order to the operation explained above.
However, to solve problems such as when the automatic document feeder 2 is unexpectedly closed during opening thereof, the conventional hinge apparatus 10 and 10xe2x80x2 as explained above should have the structure such that the elastic spring 25 presses the position-fixing plate 23 against the position-fixing cam 17 having the cam surfaces 21 and 21xe2x80x2, 22 in the form of curved and flat surfaces, i.e., the structure such that the elastic spring 25 entirely prevents the automatic document feeder 2 from unexpectedly falling and closing by its own weight. Accordingly, the elastic spring 25 should be designed to have an elastic force strong enough to endure the whole weight of the automatic document feeder 2. Thus, to ensure that the elastic spring 25 has the sufficient elastic force, the size of the elastic spring 25 should be enlarged, or the number of elastic springs 25 should be increased. However, this in turn results in a problem that a size of the hinge apparatus is enlarged. If the size of the hinge apparatus is enlarged, manufacturing costs are not only increased, but also applying the hinge apparatus to small office machines requiring a compact structure is almost impossible.
Accordingly, it is an object of the present invention to provide an improved hinge apparatus to open and close an upper member used in an office machine which can not only provide a compact and simple structure, but also can prevent the upper member from unexpectedly falling and closing during opening thereof, by elastically restraining the rotation of the upper and lower hinges from an axis direction of the hinge shaft as well as a direction perpendicular to an axis of the hinge shaft.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and other objects of the present invention may be achieved by providing a hinge apparatus to open and close an upper member such as an automatic document feeder or an upper cover used in an office machine, comprising: an upper hinge fixed on the upper member; a lower hinge fixed at a main body of the office machine; a hinge shaft to rotatably support the upper and lower hinges with respect to each other; and a position-fixing member to fix the upper member in at least one position opened at a predetermined angle by restraining the upper and lower hinges from rotating with respect to each other when the upper member is opened, the position fixing member having a first fixing part to restrain the rotation of the upper and lower hinges from a direction perpendicular to an axis of the hinge shaft and a second fixing part to restrain the rotation of the upper and lower hinges from an axis direction of the hinge shaft.
In an embodiment of the present invention, the first fixing part comprises: a position-fixing cam integrally formed with one of the upper and lower hinges and having at least one cam surface; a position-fixing plate member to maintain the upper member in the position opened at the predetermined angle by engaging with the cam surface of the position-fixing cam when the upper member is opened at the predetermined angle; and at least one first elastic spring disposed between the position-fixing plate member and the other of the upper and lower hinges to elastically press the position-fixing plate member toward the cam surface of the position-fixing cam.
The position-fixing cam is integrally formed with the upper hinge and provided with a penetrated bore to receive and support the hinge shaft, first and second fixing cam surfaces, and a guide cam surface, and the position-fixing plate member comprises at least one position-fixing plate having an upper surface to engage with the cam surfaces of the position-fixing cam to settle the position of the upper member or guide the movement thereof. In another aspect of the present invention, the first and second fixing cam surfaces of the position-fixing cam and the upper surface of the position-fixing plate are formed as flat surfaces, respectively, and the guide cam surface is formed as a curved surface. In another aspect, each of the first and second fixing cam surfaces of the position-fixing cam and the upper surface of the position-fixing plate are formed respectively as concave and convex surfaces to settle the position of the upper member.
The second fixing part comprises: a movement body coaxially disposed with the hinge shaft in the penetrated bore of the position-fixing cam to receive and support the hinge shaft, and formed to be movable in the axis direction by one of hinge shaft supporters formed at both sides of the other of the upper and lower hinges when the upper member is opened; a rotation-restraining brake coaxially disposed with the hinge shaft in the penetrated bore of the position-fixing cam to restrain the rotation of the upper and lower hinges about the hinge shaft by pressing the other of the hinge shaft supporters through the position-fixing cam of one of the upper and lower hinges according to the movement of the movement body; and a second elastic spring disposed between the movement body and the rotation-restraining brake to elastically press the movement body and the rotation-restraining brake toward the corresponding hinge shaft supporters, respectively.
The second fixing part can further include an engaged operation portion to make the movement body be engaged and moved with the position-fixing cam, and an axis operation portion to make the movement body movable in the axis direction by one of the hinge shaft supporters when the upper member is opened. The engaged operation portion comprises at least one slide projection formed at one end of either the movement body or the penetrated bore of the position-fixing cam, and at least one projection-receiving groove formed corresponding to the at least one projection on the other surface of either the movement body or the penetrated bore of the position-fixing cam.
The axis operation portion comprises at least one slide projection formed to be projected as much as the given distance which the second elastic spring is to be pressed by the movement body, at one end of either the movement body or one of the hinge shaft supporters, and a slide projection-receiving groove formed corresponding to the slide projection at the other end of either the movement body or one of the hinge shaft supporters, to enable the movement body to move in the axis direction of the hinge shaft by engaging with the slide projection when the upper member is rotated.
The movement body is formed in a cylindrical shape having a first penetrated bore formed in an inner diameter corresponding to a diameter of the hinge shaft toward one of the hinge shaft supporters to receive the hinge shaft, and a second penetrated bore formed toward the other of the hinge shaft supporters to pass the hinge shaft and support the second elastic spring.
The rotation-restraining brake is formed in a cylindrical shape having a third penetrated bore formed toward one of the hinge shaft supporters to pass the hinge shaft and support the second elastic spring, and a fourth penetrated bore formed in the inner diameter corresponding to the diameter of the hinge shaft toward the other of the hinge shaft supporters to receive the hinge shaft.
The upper hinge comprises a fixing frame having projected brackets screwed on fixing bosses formed at one side of a lower surface of the upper member.
The lower hinge comprises a hinge body settled in a mounting groove formed in the main body of the office machine and having a receiving opening to receive and support the position-fixing plate member and the first elastic spring.